Light-sensitive polymers



June 21, 1966 G, w LEUBNER ETAL 3,257,664

LIGHT-SENSITIVE POLYMERS Filed Oct. 23. 1961 Fig./

l Hmm HN ml mmm m 30o 40o soomp POLY(VINYL ACETATE BENZOATE CINNAMYLIDENEACEIATE) Fig. 2

um www lm lm www m 300 400 500 rn ,u POLY (VINYL ACETATE BENZOATE CINNAMYLIDENEACETATE) SENSITIZED WITH 4(p- AMYLOXYPHENYL)2,6BlS(pETHYLPHENYL) THIAPYRYLIUM PERCHLORATE Fig. 3

\ Hummm lm 40o 500m ,u POLY(VINYL ACETATE BENzoATE CINNAMYLIDENEACETATE) SENSITIZED WITH 4- (p- A MYLOXYPHENYL) 2,6- BIS (p-METHOXYPHENYL) THIAPYRYLIUM PERCHLORATE GERHARD W LEUB/VER CORNELIUS C. UNRUH IN VEN TORS` ATTUR/VEY 8 AGENT v all sensitiv-ity and also to increase United States Patent() 3,257,664 LIGHT-SENSITIVE PLYMERS Gerhard W. Leubner and Cornelius C. Unruh, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, NY., a corporation of New Jersey Filed Oct. 23, 1961, Ser. No. 146,742 21 Claims. (Cl. 96-115) This invention relates to light-sensitive polymers for projection speed photoresist materials and particularly to light-sensitive polymers containing recurring al-kapolyenoate groups..

It is known in the art of photomechanical reproduction to utilize various materials such as bichromated shellac, albumen or polyvinyl alcohol for forming resist images upon various supports, such as metal plates. The support is then etched or otherwise treated in areas not covered by the resist image and Ithe resultant plate ususally after removal of the resist image, is -used for printing. One method of forming relief images on metal supports is disclosed in the Murray U.S. Patent 1,965,710, granted July l0, 1934, and includes using as a sensitive layer for `forming a resist image, a layer of cinnamal ketone containing another resinous material which after exposure to activating radiation under a design may be selectively dissolved in the unexposed area whereby the area of the support thus bared may be etched.

The .use of sensitized cinnarnic acid esters of polyvinyl alcohol as the radiation-sensitive polymer in compositions `for coating photoresist materials has been described by Minsk et al. in U.S. Patent 2,610,120, granted Sept. 9, 1952.

Light-sensitive polymers known heretofore have usually been sensitive to radiation primarily in the ultra-violet regions of the spectrum. It is known to add sensitizing materials to these polymers in order to increase their overtheir sensitivity lto radiation o longer wavelengths toward'the visible portion of the spectrum.

Many light-sensitive polymers available heretofore have not had the inherent sensitivity or have not been capable of being sensitized sufficiently, especially to radiation in the visible or near visible region of the spectrum.. Increasing the sensitivity of such systems into the visi-ble region of the spectrum has several advantages: lt makes available inexpensive and convenient light sources, such as incandescent lamps, it reduces over-all exposure time, and allows projection printing through various optical systems. Projecting printing is necessary where image enlargement or reduction is required. Vacuum frames needed for contact printing are not required for projection printing.

lt is, therefore, an object of our invention to provide a new class of polymers which have an unusually high inherent sensitivity to radiation especially in the near visible region of the spectrum.

Another object is to provide a new class of `polymers which not only have unusually good inherent spectral sensitivity but which can be optically sensitized with a large number of sensitizers to an unusually large degree. Another object is to provide light-sensitivehlm-forming polymers which are valuable for making photoresist materials that are unusually valuable for projection exposures made with tungsten illumination in glass optical systems.

Still another object is to provide a new class of photoresist materials that are valuable for making printed circuits, photoengraving plates, oiset lithographs, etc.

Still further objects will become apparent from the following specication and claims.

These and other objects can be accomplished according to our. invention by the use of 'film-forming light-sensitive polymers containing recurring alkapolyenoate groups.

The alkapolyenoate groups are represented advantageously by the formula wherein R represents an aromatic group, such as a phenyl group, eg., phenyl, 4-methoxyphenyl, Z-methoxyphenyl., B-methoxyphenyl, 2-ethoxyphenyl, 3,4-dimethoxyphenyl, 2,3-dimethoxyphenyl, 2,4-dimethoxyphenyl, 2,5-dimethoxyphenyl, 3,5-dimethoxyphenyl, 4-dimethylaminophenyl, 4-diethylaminophenyl, 4-chlorophenyl, Z-chlorophenyl, 3- bromop-henyl, 4 bromophenyl, 3,4 dichlorophenyl, 2,4- dichlorophenyl, 3-nitrophenyl, 2,4-dinitrophenyl, 5-chloro-Z-nitrophenyl, etc., a naphthyl group, e.g., l-naphthyl, Z-naphthyl, 2-ethoxy-1-naphthyl, Z-methoXy-l-naphthyl, 4,8-dimethoxy-l-naphthyl, 2,7-dimethoxynaphthyl, 1,4-dimethoxy-Z-naphthyl, 6-methoXy-2-naphthyl, 4-chloro-1- naphthyl, 2-chloro-1-naphthyl, 4-bromo-1-naphthyl, 5- bromo-l-naphtlhyl, l-bromo-Z-naphthyl, 5-bromo-2-naphthyl, 4-nitro-l-naphthyl, l-nitro-Z-napht'hyl, etc., an anthranyl group, c g., 9-anthranyl, 10-methyl-9-anthranyl, etc.; and a pyrenyl group; and a heterocyclic group, such as a 2-furyl group, e.g., 2-furyl, S-methyl-Z-furyl, 5- bromo-Z--uryL S-chloro-Z-furyl, 5-iodo-2-furyl, S-nitro- Z-'furyL etc.; a Z-thienyl group, eg., 2-thienyl, S-bromo- Z-thienyl, 3,4-dichloro-2-thienyl, 5-nitr0-2-thienyl, etc., a l-methyl-Z-pyrrolyl group, a pyridyl group, e.g., Z-pyridyl, B-pyridiyl, L1f-pyridyl, 6-met-hyl-2-pyridyl, etc., n is the integer 2 or 3.

The alcohol portion of our polymers containing recurring alkapolyenoate groups can be furnished by any hydroxy-containing polymer. Especially useful hydroxycontaining polymers for the .purposes of our invention are polyvinyl alcohol, its copolymers, cellulose and oellulose derivatives.

Our preferred polymers include from 5 to 100 mole percent of vinyl ester units of an acid selected from those having the formula:

OII

in which i?. and n are as defined previously, and from 0 saturated monomer containing the radical:

such as ethylene, vinyl acetate, vinyl benzoate, vinyl chloride, vinyl alcohol, vinyl cinnamate, methyl acrylate, etc.

Included among our hlm-forming light-sensitive polymers are those having recurring groups consisting of aromatic and heterocyclic substituted or unsubstituted alkapolyenoic acid esters of polyvinyl alcohol represented by the formula:

wherein R and n are as defined previously, such that the said recurring groups comprise from 5 to 100 mol. percent of the polymer and the remainder consists of at least one intralinear group, such as an ethylene group; a vinyl alcohol group; a vinyl ester group in which the acyl group is derived from an alkanoic acid having from 1 to 18 carbon atoms, e.g., formic, acetic, bromoacetic, sulfoacetic, ethoxyacetic, o-nitrophenylacetic, p-nitrophenoxyacetic, propionic, -chloropropionic, s-uccinic, sulfosuccinic, glutaric, adipic, cyclohexanecarboxylic, sebacic, decanoic, stearic, l2hydroxystearic, an alkenoic group having from 1 to 18 carbon atoms, e.g., acrylic, fumarie, methacrylic, crotonic, glutaconic, undecenoic, oleic, ricinoleic, cinnamic, m-sulfocinnamic, an alkapolyenoic group, e.g., linoleic, linolenic, etc., an aromatic carbonyl group from aromatic acids, such as benzoic, chlorobenzoic, p-nitrobenzoic, ethoxybenzoic, o-sulfobenzoic, phthalic, 3-nitrophthalic, salicylic, sulfosalicylic, bromoterephthalic, naphthoic, 4-chloro-l-hydroxy-Z-naphthoic, 3phenanthrene, etc., a heterocyclic carbonyl -group from heterocyclic acids, such as Z-uroic, nicotinic, quinaldic, 7-chloro-4-hydroxy-3-quinolinecarboxylic etc., an esteramide of carbonio acid, such as carbamates formed by reaction of isocyanates with hydroxyl groups, e.g., carbethoxymethylcarbamate, etc., a vinyl acetal formed `from aliphatic or aromatic aldehydes having from 1 to 18 carbon atoms, such -as acetaldehyde, butyraldehyde, benzaldehyde, 4-chlorobenzaldehyde, 4- methoxybenzaldehyde, 4-dimethylaminobenzaldehyde, 1- naphthaldehyde, etc., and a vinyl ether.

Also included among our film-forming light-sensitive polymers are the aromatic and heterocyclic substituted or unsubstituted alkapolyenoic acid esters of cellulose derivatives.

Among the preferred film-forming light-sensitive polymers of our invention are the following illustrative examples which are not to be considered as limiting our invention.

Poly(vinyl cinnamylideneacetate) Poly(vinyl benzoate cinnamylideneacetate) Poly(vinyl cinnamate cinnamylideneacetate) Poly( vinyl carbethoxymethylcarbamate cinnamylideneacetate) Poly(vinyl acetate benzoate cnnamylideneacetate) Poly(vinyl acetate cinnamylideneacetate) Poly(vinyl acetate benzoate 7phenyl-2,4,-heptatrienoate) Poly(ethylene vinyl cinnamylideneacetate) Poly/(vinyl butyral cinnamylideneaeetate) Cellulose acetate cinnamylideneacetate Cinnamylideneacetate of hydroxyethyl cellulose These polymers are prepared by the esterieation of hydroxy containing polymers with cinnamylideneacetyl chloride in -an organic solvent such as pyridine. Modification reactions can be carried out with part of the hydroxyl groups of the polymers either before or after this esterication.

Our light-sensitive polymers containing recurring units of aromatic or heterocyclic substituted alkapolyenoate groups are distinguished from other polymers by having unexpectedly high sensitivity to radiation and especially to radiation of longer wavelengths, that is into the near visible and visible portions of the spectrum. The polymers of our invention are still further differentiated fromsome of the known polymers bythe greater degree to which their sensitivity can be increased by optical sensitizers.

The following example will serve to illustrate these distinguishing properties with a typical homopolymer.

Example I A coating dope was prepared consisting of a 2% solution of poly(vinyl cinnamylideneacetate) in chlorobenzene. This dope was whirl-coated horizontally at 78 r.p.m. on a silicated grained aluminum sheet. After drying, a portion of the coating was exposed to a 95-ampere carbon are light through a silver step tablet having approximately 0.15 density unit increments. The exposed coating was then tray developed in chlorobenzene for 2 minutes to dissolve the uncrosslinked polymer. This was followed by a one minute rinse in fresh solvent and the image was dyed with Kodak Photoresist Dye Bath.

Another portion of this coating dope was sensitized by adding 10% by weight of N-phenylthioacridone. This was coated, exposed and developed as described to produce a good image of the silver step wedge. Coatings were made in the same manner for sensitized and unsensitized coating dopes containing poly(vinyl cinnamate) in place of the poly(vinyl cinnamylideneacetate). These coatings were exposed by the procedure described and given a standard development.

Relative speeds were determined for each of these coatings by comparison of the developed images in each coating with the image obtained in the coating of unsensitized poly(vinyl cinnamate) which was arbitrarily given a speed of l.

The spectral sensitivity of these coatings was determined by exposing strips for 1 minute through a 1 mmgslit aperture in a spectrograph provided with a high pressure xenon arc continuous spectrum light source and a step wedge of Inconel metal on a quartz plate. After exposure, the strips were developed in chlorobenzene and dyed in the same manner as the sensitivity strips.

Relative speeds, the spectral sensitivity ranges and peaks for each of these coatings are given in Table I.

The relative speed of 900 for unsensitized poly(vinyl cinnamylideneacetate) is unexpected from the relative speed of 1 obtained for unsensitized poly(vinyl cinnamate) which differs `from our polymer only by one phenylthioacridone sensitized poly(vinyl cinnamate) is still more marked by the respective relative speeds of I1800 and the spectral sensitivity range of 240 mp. and

mate) which is 320 my..

The following exampleiwill illustrate further how our polymers are differentiated from poly(vinyl cinnamate) in their ability to be spectrally sensitized by various sensitizers.

Example II were sensitized by adding l percent of the sensitizer `The following examples will further illustrate our inindicated in Table II. vention by description of the synthesis used to prepare Spectrograms were made for each coating by exposure the polymers deSCllbed in EXmPeS 1, 2 and 3- as described in Example I. The spectral sensitivity ranges Example IV for each coating are given iii the following table: 5 Poly (vinyl cinntimylideneacemte).-A mixture of 22 TABLE Il Poly(vinyl P0ly(viriyl Polymers Sensitized Poly (vinyl benzoate cinuainyloiunamylidenewitliciiiiiamate) ideiieaeetate) acetate) No seiisitizer 285-335 275-385 275-410 N-pheiiyltliioaeridone 260-340 28o-520 Methyl(-inethyl-Z-benzothiazoliiiylldene) ditliioacetate G-330 280-500 280-500 phenylthiapyrylium 275-530 QSO-525 perchlorate. :MP500 i 2,6-bis(p-ethylpheiyD-- 29o 30 thiapyrylium perchlor- 450-480 290 550 290 510 ate. 2,6-bis (p-ethylphenyl) -4- l 290340 pyryliuiii perchlorate. l 904180 i The following example will furthcrillustrate the valug, 0f polyvinyl alcohol and 20() mL of pyridine was heated able characteristics shown by photoresist materials coated on a steam bath for 1 hour with stirring, After adding with coating dopes made according to our invention. 30 200 ml. additional pyridine and cooling to 25 C., 96.3

,f5-an e 11 g. vof melted cinnamylideneacetyl chloride was added Photosst Coatings were made from ve different dropwise with stirring. After the temperature reached dopes consisting of 2% solutions of each polymer indi- 50 C" It was mauftdmed there with cooling' Addmm cned in Tame IH Coatings were also made of each of the acetyl chloride required about 15 minutes, Tue

n o of these dopes which had been sensitized with 10% of 35 mamon .mxxtuwas then heatd on a .50 bath for 4 the sensitizerndicadin the Table HI hours with stirring. It was diluted ywith 800 ml. of

An unsenS-mzed `Coating of polywinyl Cinnama) was acetone, precipitated into approximately 10 liters of water and washed 5 times with approximately 5 liter portions of water and 1 hour stirring periods. The product was then dried at room temperature in a vacuum oven. A

made as above.

The relative speeds were determined for each of these coatings as described in Example I based on the speed of 1 for unsensitized poly(vinyl cinnamate). ylelq of 90'? grams (,90670) Was Obtamed Wedge Spectrograms were mad6 by the Pmdure de Cinnamylideneacetic.acidwas prepared .as follows: scribed previously. Table 111 summarizes the relative angolmfyglgelh gli i I b' d. g. Spetds and Spectml Sensmvlty ranges O tame stirred until solution occurred. Then 0.5 g. of piperidine TABLE IH was added and the mixture was allowed to stand at room Spectral temperature for one day: A solid cake of crystalline Polymer Sensmm rtselijteie material formed. The mixture was then reuxed for 16 m hours. After cooling, the solution Was poured into cold dilute hydrochloric acid. The resulting solid was washed Poiyiviuyi einnamyii- Non@ soo 28Min 50 With water, and the wet filter cake crystallized from 65o G bswthylphenyl 4 500 28,) 540 ml. of ethyl alcohol to give 171 g. of cinnamylideneacetic etpn-emyioxyacid, melting point 164166 C.

Cinnamylideneacetyl chloride was prepared as follows:

eiimaixiylideneacetate), -50 mol. percent method of Staudinger and Schneider, Ber., 56, 706 2 0'00 29,) 540 (1923), and puried by distillation under reduced prestate), 50-50 mol. perlOned earlier.

cent.

p0 2,-pism-etiiyipiieiiyi) 6,500 eso-540 Example V 4-(p-n-amyl0xy- Poly(vinyl benzoate cinnamylideneacetate) .--A suspenroiytviiiyiciirbetimy- Non@ G50 28H90 65 Sion of 22 g. of high molecular weight, completely hydrolyzed poly(vinyl alcohol) in 380 ml. of pyridine was nite),5o50 motperswollen by heating ori a steam bath. After cooling to enDt ggi,is(p anisyi) 4 p- 0,000 2904,00 30 C., 59 g. ot cinnamyl'ideneacetyl chloride was added slowly maintaining the temperature below 50 C. Fifteen I.' 4 i chlorine. r s minutes after the addition was complete 34.1 g. of benzoyl Polyvllymcmf um' None 00 2 0390 chloride was added and the lreaction mixture was heated nanylidene-aeetate). 4 l 6 500 280 550 50 C f 41 Th t. t h

o -p -nami/ Oxyi at or iours. e reac ion mix ure was t en hen 7l 2,6bis 4- thyispiienymhidiluted with 700 ml. of acetone and precipitated in cold rlggyhum Faremo water. After four water washes the polymer was dried under vacuum at room temperature.

Po/y(vilzyl ce1/'bethoxymethylcarbamate cmzamyldeneacetate).*This polymer was prepared by the reaction described in Example VII using 58.9 g. of cinnamylideneacetyl chloride followed by 31.3 g. of carbethoxymethylisocyanate.

Sensitivity data for this previously in Table III.

The following examples will further illustrate our invention by description of other representative examples of our polymers including their synthesis. These are not to be considered as limiting our invention.

Example VII Poly( vinyl cin/zanzare cnnamylidelzeacetate).--To a mixture of 22 g. of a medium molecular weight poly(vinyl alcohol) which had been swollen in 380 ml. of pyridine by heating on a steam bath overnight was slowly added 51 g. of cinnamoy-l chloride at 30-40 C. This was calculated to give 50 mol. percent cinnamoylation and react with the water present in the pyridine and the poly ('vinyl alcohol). Ten minutes after the addition had been completed 46.7 g. of cinnamylideneacetyl chloride was added keeping the temperature below 50 C. The reaction mixture was then heated at 50 C. for 4 hours. The dope was then diluted with 700 ml. of acetone and precipitated into cold water. The polymer was washed four times with water and dried in the vacuum oven at room temperature over calcium chloride.

A 7% dope of the polymer in a mixture of three parts of methyl Cellosolve acetate and one part of cyclohexanone sensitized with 2% of 4-(p-n-amy1oxypheny1)-2,6 bis( p-ethylphenyl)thiapyrylium perchlorate gave coatings on copper or other metals circuit or other applications. For example, such a coating could be given an exposure of about 500 foot candle minutes to a projected tungsten light image enlarged 8 times the original negative size. Previously described light-sensitive polymers would require considerably longer exposures and in many cases would require an ultraviolet light source. Following the exposu-re, the coating was developed in a vapor degreaser with trichloroethylene to give a lhigh quality resist image suitable for further treatment such as etching or printing depending on the application desired.

polymer were summarized Sensitivity data for this polymer aresummarized in Table III.

The results of variation of the cinnainate-cinnamylideneacetate ratio on sensitivity are shown in Table 1V. The various copolymers were made yby appropriate adjustments in the amounts of cinnamoyl chloride and cinnamylideneacetyl chloride used in the reaction described. The relative speeds given are compared to unsensitized poly(fv|inyl cinnamate) made from a Du Pont medium molecular weight poly(vinyl alcohol), Elvanol 90-25, which was arbitrarily given a value of 1. The polymer samples in Table IV were prepared from another medium molecular weight poly(.viny1 alcohol), Du Pont Elvanol 71-30. Poly(vinyl cinnamate) prepared from this poly (vinyl alcohol) has approximately half the sensitivity of that made from the earlier mentioned starting polymer.

TABLE IV Mole Percent Relative Speeds NR Cinnnniatc Cinnamylidcne- Unsensitizcd Sensitizcd acetate with high sensitivity for printed .8 The polymers listed in the above table were sensitized with 2,6-bis[pethylphenyl]-4-(p-amyloxyphenyl)thiapyrylium perchlorate.

Example VIII P0ly(vi1zyl acetate benzoate cmzamylideneacelate).- A suspension of g. of a high molecular weight 88% hydrolyzed poly('vinyl alcohol) in 380 ml. of pyridine was swollen by heating on a steam bath. After cooling to C., 16 g. of cinnamyltideneacetyl chloride was added slowly maintaining the temperature below C. Fifteen minutes after the addition was completed, g. of benzoyl chloride was added. The amounts of the acid chlorides were calculated, taking into account the moisture in the po1y(vinyl alcohol) and the pyridine to give a composition of 10 mole percent oinnamylideneacetate, 78 mole percent benzoate and the 12 mole percent acetate. The reaction mixture was then heated with stirring at 50 C. for 4 hours. After cooling and diluting with 700 ml. of ace-tone the polymer was precipitated into water, given 4 washes with water and dried in a vacuum oven at room temperature over calcium chloride.

Poly(vinyl acetate benzoate samples were also prepared having cinnamyltideneacetate) 50 mole percent vinyl cinnamylideneacetate, 38 mole percent vinyl benzoate and also 88 mole percent weight percent`(based on the weight of polymer) of 4- amyloxyphenyl)2,6 bis(pethylphenyl)thiiapyrylium perchlorate. l

These coatings were exposed as described in Example 1 and developed in chlorobenziene. Relative speed values were determined for each of the samples. The data are summarized in the following Table V.

TABLE V Polymer Composition (mol percent) Relative Speed Vinyl ein- Vinyl Vinyl Unscn- Sensinamylidene- Benzoate Acetate sltized tizcd acetate A 10 percent dope of poly(vinyl acetate benzoate cinnamylideneacetate), 12 mol. percent acetate, 78 mol. percent benzoate, and 10 mol. percent cinnamylideneacetate, 1n a mixture of three parts of n-butyl acetate and two mol. percent cinnamylideneacetate, sensitized with 2 percent of the above-mentioned sensitizer, gave coatings on copper or other metals with high sensitivity for printed circuit or other applications.

In stil-l another embodiment of our invention a 3 per- The dried coating was exposed for about 3 to 6 seconds through a positive transparency using a sunlamp at a distance of 14 inches. The image was devel- 0 oped by washing the element in methyl ethyl ketone. The

Example IX Plyf(vnyl acetate cnnnmylideneaee'tate).-This polymer was prepared in the sam-e manner as the poly(vinyl acetate benzoate cinnamylidene acetate) described in Example VHI using acetic anhydride in place of benzoyl chloride in an amount calculated to give 50 mol. percent acetate. Coated from and developed in chlorobenzene, this sample and a sample sensitized with 4-(p-n-amyloxyphenyl)-2,6bis(pethylphenyl) thiapyrylium perchlorate gave th-e relative speeds and spectral sensitivities summarized previously in Table III.

Example X P0ly(v1'nyl acetate benzorlte 7-pzenyl-2,4,6lzeplatrenoare) .-This polymer was prepared by the same procedure used in Example VIH using 7-phenyl-2,4,6-heptatrienoyl chloride in place of cinnamylideneacetyl chloride. Amounts of reactants were used to give a polymer containing l2 mol percent acetate, 48 mol percent benzoate,

and 40 mol percent of the phenylheptatrienoate.

A 2 percent solution of the resulting polymer in chlorobenzene coated on aluminum when exposed to a sunlamp through a line negative, followed by development in chlorobenzene and dyeing gave a positive image.

The 7-phenyl-2,4,6-heptatrienoyl chloride, MP. 90 C., was prepared from the corresponding acid in the same manner as cinnamylideneacetyl chloride. The 7-phenyl- 2,4,6-heptatrienoic acid was prepared in the following manner: To a solution of sodium meth-oxide from 7.7 g. of sodium in 200 ml. of methanol was added with stirring during 10 minutes a solution of 26.4 g. of 5-phenyl-2,4- pentaidenol, I. of Gen. Chem. (USSR) 29, 2526 (1959), 37.3 g. of 0,0-diethylcarbethoxymethylphosphonate and 50 ml. of methanol. After refluxing this mixture for 21/2 hours, it was diluted with ml. of distilled water and refluxed 2-1/2 hours longer. The produ-ct was isolated by cooling and pouring slowly with vigorous stirring into a mixture of 50 ml. concentrated hydrochloric acid, 500 ml. of distilled water and 200 g. crushed ice. The solid was collected, washed with water, dried under vacuum at 50 C. and recrystallized from 300 ml. of toluene to give 15.2 g. of product melting at 190-193 C.

Example Xl A copolymer of vinylacetate and ethylene was prepared as described in Example l of Minsk et al. U.S. Patent 2,801,233, granted luly 30, 1957, containing approximately 10 mol percent of ethylene. The polymer was deacetylated in the manner described in the same example to give a copolymer of vinyl alcohol and ethylene also containing about 10 mol per-cent orP the latter component. This was a White, fibrous polymer.

Ten grams of this copolymer was heated for 4 hours in 100 ml. of dry pyridine on a steam bath. Upon cooling to 40 C., 50 g. of cinnamylideneacetyl chloride was added portionwise with stirring. The reaction mixture was then heated for 4 hours at 50 C. The p-olymer was isolated by diluting with 2 volumes of acetone, precipitating into water, washing several times with water and drying at room temperature in vacuo in the dark.

A coating of the polymer on brushed aluminum obtained from a 2 percent solution in chlorobenzene when exposed to a sunlamp through a line negative, followed by development in chlorobenzene and dyeing gave a positive image. The sensitivity of the polymer was greatly enhanced when sensitized with various sensitizers.

Example XII Poly(vinylbulyral cinnam'ylideneacelate).-Ten grams of a poly(vinylbutyral) containing 22 percent by weight of vinyl alcohol units was dissolved in 100 ml. of pyridine it? and treated as in Example XI with 13 g. of cinnamylideneacetyl chloride.

A coating of the resulting polymer was light sensitive, forming an image following the usual steps of exposure, solvent development and dyeing.

The following examples illustrate typical representative polymers in which a cellulose or a cellulose derivative is esteried with an alkapolyenoic acid.

Example XIII Cellulose acetate cinnamyldeneacetate--To a solution of 11.8 g. (0.05 mole) of cellulose acetate (32.4 percent Ac) in ml. of pyridine was added 19.3 g. (0.1 mole) cinnamylideneacety-l chloride dropwise with stirring. The temperature rose to 56 C. The reaction mixture was then heated at 50 C. for 4 hours. The reaction dope was then diluted with 200 ml. of acetone and precipitated into 3 l. of water. The resul-ting polymer was washed four times with water and dried in a vacuum oven at room temperature. When tested in the usual manner for light sensitivity, this sample gave a relative speed of 80.

Example XIV Clmamyldeneazcetate of lzyd1oxyetl1yl cellulose- A mixture of v6.2 g. of hydroxyethyl cellulose (carbide and carbon, Cellosize WP-3) and 75 ml. of pyridine was heated -on a steam bath with stirring. After cooling to room temperature 17.3 g. of cinnamylideneacetyl chloride was added dropwise with stirring in 15 minutes. During the addition, the temperatur-e was maintained at approximately 50 C. with cooling. After addition was complete, the reaction mixture was heated in a 50 C. bath for 4 hours. It was then diluted with 190 ml. of acetone and precipitated into 2 l. of water. The polymer was washed 4 times withwater and .dried in a vacuum oven at room temperature. On testing for light sensitivity, it gave va relative speed of 450.

Other hydroxyl c-ontaining polymers such as the naturally occurring materials cellulose, starch, guar, alginic acid or their partially esteriied or etherilied derivatives, such as cellulose acetates, propionates or butyrates, mixed acetate-butyrates, hydroxyethyl cellulose, ethyl cellulose, etc., are esteriied by reaction with alkapolyenoic chlorides to produce polymers according to our invention.

The acid chlorides concerned are also capable of reacting with polymers containing amino groups, such as poly(vinylamine) copolymers, poly(vinylanthranilate), po1y'(aminostyrene), etc., as well as with naturally occurring polymers, such as gelatin to give the corresponding light-sensitive amide derivatives.

Our film-forming light-sensitive compositions are made by dissolving one or moreof our polymers in any suitable solvent or combination of solvents used in the art to prepare polymer dopes. The selection of doping solvents is restricted to solvents which will produce satisfactory coatings under the conditions used. The solvent should have a low enough boiling point so as to dry down without excessive whirling time but should have a high enough boiling point not to cause blush from moisture condensation due to too rapid evaporation. Solvents that are used to advantage include methyl Cellosolve acetate, n-butyl acetate, 2-methoxymethyl acetate, acetone, met-hylethyl ketone, 2-butanone, 2,5-hexanedione, cyclohexanone, benzene, toluene, chlorobenzene, a-chlorotoluene, methylene chloride, tetrachloroethane, etc. The same solvents or solvent mixtures are used toadvantage in the wash-off development o-f photoresist materials coated with our lightsensitive compositions.

Our polymers are used to advantage in the light-sensitive compositions in the range from about 1 to 20 percent by weight. The preferred range is from 2 to 10 percent by weight.

Our compositions are advantageously sensitized by adding sensitize-r Ifrom about 0.1 to 10 percent by Weight of the polymer. The preferred range is from about 0.5 to 3 percent of sensitizer based on the weight of polymer. Any sensitizers used in the art tooptically sensitize polymers may `be -used to sensitize our compositions. These sensitizers include the aromatic nitro sensitizer compounds described in Minsk et al. U.S. Patent 2,610,120, granted Sept. 9, 1952, such as p-nitroaniline, 2,4,6-trinitroanline, 2-chloro-4-nitroaniline, 2,6-dichloro-4-nitroaniline, etc., the anthrones, benzanthrones and azabenzanthrones described in Minsk et al. U.S. Patent 2,670,285, granted Feb. 23, 1954, such as anthrone, 2-keto-methyl-3-azo-1,9-benzanthrone, l-carbethoxy-2-keto-3-methyl-3-azabenzant-hrone, etc., the quinones described in Minsk et al. U.S. Patent 2,670,286, granted Feb. 23, 1954, such as 1,2-benzanthraquinone, 2- methyl-l,4-naphthoquinone, -phenylanthraquinone, 2,3- diphenylanthraquinone, etc., the diaminobenzophenone imides, the diaminodiphenylmethanes, the diaminodiphenyl ketones and the diaminodiphenylcarbinols described by Minsk et al. U.S. Patent 2,670,287, granted Feb. 23, 1954, such as 4,4tetramethyldiamino benzophenone imide, 4,4'- diamino-3,3-di-otolylmethane, 4,4'-tetramethyldiaminobenzophenone, 4,4'-tetramethyldiaminodiphenylcarbinol, etc., the triphenylmethanes described by Minsk et al. U.S. Patent 2,690,966, granted Oct. 5, 1954, such as Crystal Violet (Schultz No. 785), Malachite Green (Schultz No. 754), Victoria Blue B (Schultz No. 822), etc., the thi- -azoles and related cyanine dyes described by Robertson et al. U.S. Patent 2,732,301, granted lan. 24, 1956, such as 2-propionylmethylene-1-methyl--naphthothiazole, 2- (m-chlorobenzoyl-methylene)1methyl naphthothiazole, 2-benzoylmethylene-l-methylnaphthothiazole, etc.

Sensitizers particularly advantageous for optically sensitizing our polymers are the pyrylium and thiapyrylium salts described in the Van Allan, Natale and Rauner U.S. patent application, Ser. No. 146,743, filed Oct. 23, 1961, entitled Light-Sensitive Layers Containing Pyrylium and Thiapyrylium Salts, filed simultaneously with the immediate application, such as 2,6bis(pethylphenyl)-4-(p-namyloxyphenyl)thiapyrylium perchlorate, 2,6-bis(panisyl)-4-(pn-amyloxyphenyl)thiapyrylium perchlorate, etc., and the 4-oxo-l,4a-diazaphthalenes, the 4a-azanaphthalenes, the 4-oxo-1-thia-3a,7diazaindenes and the acridones described in Reynolds et al. U.S. Ser. No. 51,695, tiled A-ug. 24, 1960, now U.S. Patent No. 3,072,485, entitled Optically Sensitized Azido Polymers lfor Photomechanical Resist Compositions, such as 3-carbethoxy-G-chloro-4-oxo- 1,4a-diazanaphthalene, 6ethyl4oxo-4aazanaphthalene, 4-oXo-l-thia-3a,7-diazaindene, N-methylacridone, etc.

Other addenda may be added to our compositions, such4 as, for example, antioxidants. Antioxidants that are -used to advantage with our po1y(vinyl cinnamylideneacetate) polymers include hydroquinone and Tenox antioxidant, a butylate Ihydroxyanisole available from Eastman Chemical Products Inc. These compounds are used in amounts ranging Ifrom 0.1 to 2 percent of the polymer weight to improve the stability of the coating dopes.

.As in the case of the poly(vinyl cinnamates) (see U;S. 2,739,892), we have ifound that the adhesion to metal surfaces of essentially completely esterified cinnamylideneacetate polymers can be modified either (a) by the addition to the essentially completely esteried ester of 1-50% by weight of a partially esterified cinnamylideneacetate polymer containing poly(vinyl alcohol) groups in the ran-ge of about 20-50 mol or (b) by the use of a partially esterifed cinnamylideneacetate polymer containing free hydroxy groups in approximately 5 to 20 mol percent amounts alone.

Our invention is still further illustrated by the accompanying drawing FIG. 1, FIG. 2 and FIG. 3. Each drawing represents a wedge spectrogram for a photoresist material.

FIG. 1 represents the wedge spectrogram for a photoresist element coatedwith unsensitized 2 percent poly- (vinyl acetate benzoate cinnamylideneacetate) in chlorobenzene.

FIG. 2 represents the Wedge spectrogram for a photoresist element coated with 2 percent poly(vinyl acetate benzoate cinnamylideneacetate) in chlorobenzene sensitized with 10 percent (of weight of polymer) of 4-(pamyloxyphenyl)-2,6bis(4ethylphenyl)thiapyrylium perchlorate.

FIG. 3 represents the wedge spectogram for a photoresist element coated with 2 percent poly(vinyl acetate -benzoate cinnamylideneacetate) in chlorobenzene sensi- -tized with 10 percent (of weight of polymer) of 4-(pamyloxyphenyl)-2,6 bis (p-methoxyphenyl)thiapyrylium perchlorate.

The film-forming light-sensitive polymers containing recurring alkapolyenoate groups are distinguished from other polymer compositions 4by having unexpectedly high sensitivity to radiation especially in the near visible portions of the spectrum. For example, our photoresist elements coated with a composition containing unsensitized poly( vinyl cinnamylideneacetate) gave relative speeds that are 900 times higher than corresponding photoresist elements coated with a composition containing the prior art, unsensitized poly(vinyl cinnamate). This photoresist element of our invention had a spectral sensitivity range of mn compared to the prior art range of 90 ma. Photoresist elements coated with our polymer compositions are tfurther distinguished from the corresponding prior art compositions by being capable of sensitization with a wide range of sensitizers to much higher relative speeds and to radiation of substantially longer wavelengths.

The greatly increased sensitivity and spectral sensitivity of photoresist elements coated with sensitized cinnamylideneacetate polymers over photoresist elements coated with previously known light-sensitive polymers makes it possible and practical to use incandescent light sources for exposures and projection printing through glass optics. Projection exposures allow the enlargement or reduction of an image to be made readily on planar or uneven surfaces. This process will make possible ymany applications which formerly were impossible, extremely difficult, inconvenient, or uneconomical.

The invention has been described in detail with particbe effected within the spirit and scope of the invention enoate groups having the formula:

wherein R represents agroup selected from the class consisting of a phenyl group, a naphthyl group, an anthranyl group, a pyrenyl group a 2-furyl group, a 2- thienyl group, a 1-methyl-2-pyrrolyl group, ,and a pyridyl group, and lz is an integer from 2 to 3, said alkapolyenoate groups being attached directly to carbon atoms in the chain of said polymer.

2. A film-forming light-sensitive polymer consisting of an ester of (1) a hydroxy containing polymer selected from the class consisting of a homopolymer of vinyl alcohol, a copolymer of vinyl alcohol and a cellulose, and (2) a compound having the formula:

13 wherein R represents a group selected from the class consisting of a phenyl group, a naphthyl group, an anthranyl group, a pyrenyl group, a Z-uryl group, a 2- thienyl group, a 1-methyl-2-pyrrolyl group, and a pyridyl group, and n is an integer from 2 to 3.

3. A hlm-forming light-sensitive polymer derived from those selected from the class consisting of a homopolymer of vinyl alcohol, a copolymer of vinyl alcohol, and a cellulose, said polymer containing recurring vinyl alkapolyenoate groups selected from those having the formula:

wherein R represents a group selected from the class consisting of a phenyl group, a naphthyl group, an anthranyl group, a pyrenyl group, a 2-furyl group, a 2- thienyl group, a l-methyl-Z-pyrrolyl group, and a pyridyl group, and n is an integer from 2 to 3.

4. A hlm-forming lightsensitive polymer consisting of from 5 to 100 mol percent of vinyl alliapolyenoate groups selected from those having the formula:

wherein R represents a group selected from the class consisting of a phenyl group, a naphthyl group, an anthranyl group, a pyrenyl group, a Z-furyl group, a 2- thienyl group, a 1-methyl-2-pyrrolyl group, and a pyridyl group, an n is an integer from 2 to 3, and from 0 to 95 mol percent of units of a monoethylenically-unsaturated monomer selected from the class consisting of ethylene, vinyl alcohol, vinyl chloride, a vinyl ester, a vinyl acetal, a vinyl ether, and methyl acrylate.

5. A hlm-forming light-sensitive polymer derived from those selected from the class consisting of a homopolymer of vinyl alcohol, a copolymer of vinyl alcohol, and a cellulose, said polymer having recurring groups selected from the formula:

vinyl acetal group, a vinyl ether group and methyl acrylate.

6. A poly (vinyl cinnamylideneacetate).

7. A copolymer of vinyl cinnamate and vinyl cinnamylideneacetate.

8. A copolymer of vinyl acetate, vinyl benzoate, and vinyl cinnamylideneacetate.

9. A copolymer of vinyl carbethoxymethylcarbamate and vinyl cinnamylideneacetate.

10. A copolymer of vinyl acetate and vinyl cinnamylideneacetate.

11. A hlm-forming light-sensitive composition containing a solvent and from about 1 to 20 percent by weight of a light-sensitive polymer derived from those selected from the class consisting of a homopolymer of vinyl acohol, a copolymer of vinyl alcohol, and a cellulose, said polymer containing recurring vinyl alkapolyenoate groups.

phenylmethane, a

12. A nlm-forming light-sensitive composition containing a solvent and from about 1 to 20 percent by Weight of a light-sensitive polymer derived from those selected from the class consisting of a homopolymer of vinyl al cohol, a copolymer of vinyl alcohol, and a cellulose, said polymer containing recurring groups of the formula:

wherein R represents a group selected from the class consisting of a phenyl group, a naphthyl group, an anthranyl group, a pyrenyl group, a 2-furyl group, a 2- thienyl group, a 1-methyl-2-pyrrolyl group, and a pyridyl group, and n is an integer from 2 to 3, such that said recurring group comprises from 5 to 100 mol percent of the said polymer and the remainder consists of intralinear groups selected from the class consisting of ethylene, vinyl alcohol, vinyl chloride, a vinyl ester, a vinyl acetal, a vinyl ether, and methyl acrylate.

13. A film-.forming light-sensitive composition containing a solvent and from about l to 20 percent of a poly (vinyl cinnamylideneacetate).

14. A hlm-forming light-sensitive composition containing a solvent and from 1 to 20 percent of a copolymer of vinyl cinnamate and vinyl cinnamylideneacetate,

15. A film-forming light-sensitive composition containing a solvent and from about 1 to 20 percent of a copolymer of vinyl acetate, vinyl benzoate and vinyl cinnamylideneacetate.

16. A hlm-forming light-sensitive composition containing a solvent and from about 1 to 20 'percent of a copolymer of vinyl carbethoxymethylcarbamate and vinyl cinnamylideneacetate.

17. A lm-forming light-sensitive composition containing a solvent and from about 1 to 2O percent of a copolymer of vinyl acetate and vinyl cinnamylideneacetate.

18. A film-forming light-sensitive composition of claim 12 containing from 0.1 to 10 percent based on the weight of said polymer of an optical sensitizer selected from the class consisting of an aromatic nitro sensitizer compound, an anthrone, a benzanthrone, an azabenzanthrone, a quinlone, a diaminobenzophenone imide, a diaminodidiaminodiphenyl ketone, a diaminodiphenylcarbino, a triphenylmethane, a thiazole, apyrylium salt, a thiapyrylium salt, a 4-oXo-1,4a-diazaphthalene, a 4a-azanaphthalene, a 4-oXo-1thia-3a,7diazaindene and an acridone.

19. A hlm-forming light-sensitive coating composition comprising a mixture of (l) a copolymer of vinyl acetate, vinyl benzoate, and vinyl cinnamylideneacetate, and (2) a copolymerof vinyl alcohol, vinyl acetate and vinyl cinnamylideneacetate.

Ztl. A hlm-forming light-sensitive polymer consisting of an ester of (l) a cellulose derivative and (2) an acid chloride selected from those having the formula:

consisting of a homopolymer of vinyl alcohol, a eopolymer of vinyl alcohol, and a cellulose, said polymer containing recurring vinyl alkapolyenoate groups selected from those having the formula:

References Cited by the Examiner UNITED STATES PATENTS 2,666,701 1/1954 West 96-115 2,670,286 2/1954 Minsk et al 260*89.3 2,670,287 2/1954 Minsk et al. 96-115 2,725,372 11/1955 Minsk.

16 2,941,988 6/1960 wolf. 2,956,878 10/1960 Michiels et al. 96-33 OTHER REFERENCES Blicke, I. Am. Chem. Cov., vol, 45, pp. 1562-1566, (June 1923).

NORMAN G. TORCHIN, Primary Examiner.

PHILIP E. MANGAN, JOSEPH L. SCHOFER,

Examiners.

R. L. STONE, H. WONG, R H. SMITH,

Assistant Exmn/zers.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,257,664 June 2l, 1966 Gerhard W. Leubner et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 13, lines l2 to l5, in the structural formula, that part of the structure in line 15 that reads "(CH=CHnR" Should read (-CH=CH)HR line 34, "an", first occurrence,

should read and Signed and sealed this 5th day of May 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. JR.

Attesting Officer Commissioner of Patents 

1. A FILM-FORMING LIGHT-SENSITIVE POLYMER DERIVED FROM THOSE SELECTED FROM THE CLASS CONSISTING OF A HOMOPOLYMER OF VINYL ALCOHOL, A COPOLMER OF VINYL ALCOHOL, AND A CELLULOSE, SAID POLYMER CONTAINING RECURRING ALKAPOLYENOATE GROUPS HAVING THE FORMULA: 